DNA metabarcoding, diversity partitioning and null models reveal mechanisms of seasonal trophic specialization in a Mediterranean warbler.

Optimal Foraging Theory (OFT) predicts that a population's trophic niche expansion should occur in periods of food scarcity as individuals begin to opportunistically exploit sub-optimal food items. However, the Niche Variation Hypothesis (NVH) posits that niche widening may result from increased among-individual differentiation due to food partitioning to avoid competition. We tested these hypotheses through a DNA metabarcoding study of the Sardinian Warbler (Curruca melanocephala) diet over a year.

Maternal care according to offspring sex and maternal physical condition in mantled howler monkeys (Alouatta palliata).

The Trivers-Willard hypothesis (TWH) posits that maternal care will be biased in favor of the sex that provides the greatest fitness returns per unit of investment, depending on maternal physical condition. Our aim was to examine the TWH in mantled howler monkeys living at Los Tuxtlas (Veracruz, Mexico). The biological attributes of mantled howler monkeys (Alouatta palliata) meet the assumptions of TWH better than those of other explanations, so we expected that females in better physical condition should bias maternal care toward sons, whereas mothers in worse physical condition should bias care toward daughters.

A new species of terrestrial frog (Strabomantidae) from the upper basin of the Pastaza River, Ecuador.

We describe a new species of from the montane forest of the Río Zuñag Ecological Reserve, upper basin of the Pastaza River, Ecuador. is characterized by a snout-vent length of 11.6-21.